Vision Parameters Most Important to Functionality in Glaucoma

PURPOSE: To determine the importance of various vision parameters to functionality in glaucoma. METHODS: Vision was measured using seven parameters: visual acuity (VA), contrast sensitivity (CS), integrated visual field (IVF), area under the log CS function (AULCSF), color vision, stereoacuity, and VA with noise (ViN). Likelihood ratio testing (LRT) determined if the full set of visual parameters significantly explained variability in 10 functional outcomes. For outcomes where the visual contribution was significant, dominance analysis determined the relative importance of the various visual parameters. RESULTS: The analysis included 151 glaucoma patients. Mean age was 70 ± 6.8 years, and 47% were men. Significant visual contributions (LRT P < 0.05) were noted for glaucoma quality of life (GQL-15), reading speed, driving cessation, daily steps, and base of support while walking, but not for fear of falling, balance, gait velocity, stride velocity, and stride length while walking (LRT P > 0.05). The most important parameter (and percent contribution) to vision-explained variability were AULCSF for daily steps (45%), IVF for base of support (35%), VA for reading speed (34%), CS for GQL-15 (30%), and VA for driving cessation (26%). CONCLUSIONS: Measures of visual ability are important for several aspects of quality of life and functionality. The most important vision parameter for functionality differs depending on the domain studied. Reading and driving were explained by VA and IVF sensitivity. On the other hand, GQL-15 and daily steps were more heavily influenced by CS and AULCSF, which are rarely performed clinically.